Commonly-owned DE 32 17 406 C2 (U.S. Pat. No. 4,528,848) discloses metering apparatus for continuous gravimetric metering of pourable material passed through a charge tunnel to a rotor driven about a vertical rotational axis, and removed through a discharge region offset in a rotational direction to said charge tunnel, said rotor being supported pivotably about an essentially horizontal pivot axis and being connected to a force measuring device arranged at distance from said pivot axis.
In this metering apparatus, the rotor comprises a plurality of receiving pockets which are discharged by supplying pressurized air. Such a metering apparatus is particularly adapted for coal dust metering in burning processes. However, the metering apparatus suggested there is of relative complex design due to the additional pneumatic feeding system for supplying pressurized air and in view of the elastic connecting elements necessary for the free pivotal movement of the rotor. Furthermore, there is a tendency for dome-forming in the pockets of the cellular rotor with pourable material having high humidity or with sticky pourable material, resulting under unfavourable conditions in an insufficient discharging of the pourable material.